This invention generally relates to slider-operated flexible zippers for use in reclosable pouches, bags or other packages of the type in which perishable material, such as foodstuff, may be stored.
Reclosable fastener assemblies are useful for sealing thermoplastic pouches or bags. Such fastener assemblies often include a plastic zipper and a slider. Typically, the plastic zippers include a pair of interlockable fastener elements, or profiles, that form a closure. As the slider moves across the profiles, the profiles are opened or closed. The profiles in plastic zippers can take on various configurations, e.g. interlocking rib and groove elements having so-called male and female profiles, interlocking alternating hook-shaped closure elements, etc.
Conventional slider-operated zipper assemblies typically comprise a plastic zipper having two interlocking profiles and a slider for opening and closing the zipper. In one type of slider-operated zipper assembly, the slider straddles the zipper and has a separating finger at one end that is inserted between the profiles to force them apart as the slider is moved along the zipper in an opening direction. The other end of the slider is sufficiently narrow to force the profiles into engagement and close the zipper when the slider is moved along the zipper in a closing direction.
Other types of slider-operated zipper assemblies avoid the use of a separating finger. For example, U.S. Pat. No. 5,809,621 discloses a slider-operated zipper assembly wherein one zipper profile has a pair of handles that cooperate with the slider. As the slider is moved in an opening direction, the handles are squeezed together to disengage the profiles. In U.S. Pat. No. 5,442,838, a slider-operated zipper assembly is disclosed wherein the zipper profiles are engaged and disengaged in the course of a xe2x80x9crolling actionxe2x80x9d. This xe2x80x9crolling actionxe2x80x9d is described as being achieved through cooperation between flanges on the profiles and shoulders which project inwardly from the arms of the slider.
There is a need for a slider-zipper assembly design that would allow packaging film to be sealed directly to the exterior of the zipper parts without interfering with the operation of the slider. There is a further need for a slider-zipper assembly design that lends itself well to being sealed into the center fold of a packaging film.
The invention is directed to a slider-zipper assembly for reclosable packaging in which the slider is mounted inside the zipper. Slider-zipper assembly designs are disclosed that allow packaging film to be sealed directly to the exterior of the zipper parts without interfering with the operation of the slider. Being able to seal the packaging film to the outside of the zipper parts makes it easier to incorporate header features that are typically used to provide evidence of tampering. Conventional extension flanges are not needed when the packaging film is joined to the backs of the zipper profiles. The disclosed designs also facilitate placement and sealing of the slider-zipper assembly in the center fold of a packaging film.
One aspect of the invention is a package comprising front and rear walls joined to first and second parts of a flexible zipper operated by a slider of the type described hereinafter. Each zipper part comprises a base and a closure element connected to the base, the respective closure elements being mutually engageable. The slider comprises a body having one end where the zipper is open and another end where the zipper is closed, a first direction being directed from the closed end to the open end and a second direction being opposite to the first direction. The slider further comprises a pair of camming surfaces that have respective fixed positional relationships to the body and are divergent in the first direction. These camming surfaces are disposed so that the zipper parts are respectively cammed toward each other as the slider is moved in the first direction. No part of the slider confronts the exterior surfaces of the bases of the zipper parts.
Another aspect of the invention is a slider-zipper assembly wherein the slider and the zipper have structures as described in the preceding paragraph.
Another aspect of the invention is a package comprising first and second walls, a zipper comprising first and second zipper parts respectively joined to the first and second walls, and a slider mounted to the zipper. The first zipper part comprises a first base and a first closure element connected to the first base; the second zipper part comprises a second base and a second closure element connected to the second base and engageable with the first closure element. The first base comprises a first groove that opens on an interior surface of the first base; the second base comprises a second groove that opens on an interior surface of the second base. The slider comprises a body and first and second ribs connected to and projecting out of opposing sides of the body, the first rib being engaged in and slidable along the first groove, and the second rib being engaged in and slidable along the second groove.
A further aspect of the invention is a slider comprising a body having first and second ends and first and second sides, a first rib projecting outward from the first side of the body and a second rib projecting outward from the second side of the body, the first and second ribs being generally co-planar and non-parallel.
Another aspect of the invention is a slider comprising a body having first and second ends and first and second sides, a first groove formed in the first side of the body and opening on an exterior surface of the first side, and a second groove formed in the second side of the body and opening on an exterior surface of the second side, the first and second grooves being generally co-planar and non-parallel.
Yet another aspect of the invention is a package comprising a folded sheet of film sealed on three sides to form an enclosed receptacle, a zipper comprising first and second zipper parts sealed to first and second opposing portions of the sheet of film in proximity to the fold in the sheet. A slider is mounted to the zipper. The first zipper part comprises a first base strip having an exterior side sealed to the first opposing portion of the sheet of film and having a first closure element connected to and projecting from an interior side of the first base strip. The second zipper part comprises a second base strip having an exterior side sealed to the second opposing portion of the sheet of film and having a second closure element connected to and projecting from an interior side of the second base strip. The second closure element is engageable with the first closure element when the slider is moved in one direction and is disengageable when the slider is moved in the opposite direction.
A further aspect of the invention is a package comprising a receptacle with a zippered mouth and a slider mounted in the zippered mouth. The zippered mouth comprises first and second ribs projecting inward from opposing sections of the zippered mouth. The slider comprises a body having first and second ends and first and second sides, a first groove formed in the first side of the body and opening on an exterior surface of the first side, and a second groove formed in the second side of the body and opening on an exterior surface of the second side, the first and second grooves being generally coplanar and non-parallel. The first groove engages the first rib and the second groove engages the second rib.
A further aspect of the invention is an assembly comprising first and second zipper parts and a slider mounted to these zipper parts, the first zipper part comprising a first closure element and the second zipper part comprising a second closure element, these closure elements being mutually engageable, wherein the slider separates the zipper parts when moved in an opening direction and closes them when moved in a closing direction, the slider being positioned entirely within the zipper parts.
Another aspect of the invention is a package comprising a web of film folded to form a header and sealed along three unfolded sides; and a slider-operated zipper disposed in proximity to the fold inside said header, the zipper comprising first and second bases sealed to the film, wherein the slider is positioned entirely within the zipper bases.
Other aspects of the invention are disclosed and claimed below.